Electrodeposited Silver Amalgam Particles on Pyrolytic Graphite in (Spectro)Electrochemical Detection of 4-nitrophenol, DNA and Green Fluorescent Protein

Abstrakt

Catalytic properties and high adsorption affinity of nucleic acids and proteins to silver amalgam electrodesurface make this kind of electrified interface perspective for bioanalytical and biomedical applications.For the first time, a basal-plane pyrolytic graphite electrode (bPGE) has been used as a substrate for elec-trodeposition of silver amalgam particles (AgAPs). Optimization of the resulting composition, surfacemorphology and electrochemical properties of the AgAPs was done by scanning electron microscopy withenergy disperse X-ray spectroscopy, image processing software and voltammetric detection of electro-chemically reducible model organic nitro compound, 4-nitrophenol. Spectro-electrochemical applicabil-ity of bPGE-AgAP has been demonstrated by electrolysis of 4-nitrophenol. Simultaneous UV–Vis-chronoamperometry provided information on the number of exchange electrons and the reduction rateconstants. Preferential adsorption of the fluorescently labelled calf thymus DNA and the green fluorescentprotein (GFP) on the surface of AgAPs was observed by fluorescence microscopy. In contrast to previouslystudied indium-tin oxide and vapour-deposited gold decorated by AgAPs, herein the presented bPGE-AgAP has provided sufficiently wide negative potential window allowing direct electroanalysis of non-labelled DNA and GFP using intrinsic electrochemical signals independently of the fluorescent labelling.The bPGE-AgAP can thus be expected to find application opportunities in protein electrochemistry, (bio)sensor development orin-situspectro-electrochemical studies.